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Framework Developed for Geomorphic Mapping of Fern Ridge Lake, Oregon, 2023

Data Report 1215
Prepared in cooperation with the U.S. Army Corps of Engineers
By:  and 
https://doi.org/10.3133/dr1215

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Abstract

The construction and operation of large reservoirs in the Willamette River Basin, Oregon, influences important cultural, biological, and other natural or economic resources in affected river corridors. The present-day landforms and cover within the reservoirs have been shaped by a variety of processes, including the pre-dam valley setting and geomorphic processes related to dam operations. Maps of reservoir geomorphic process domains, landforms, and cover provide a foundation for understanding how erosion and deposition processes in or near the reservoirs may affect cultural resources. Detailed geomorphic mapping of Fern Ridge Lake in 2023 provides a basis for evaluating geomorphic processes and patterns of sediment transfer within the reservoir. These processes are related to geomorphic and hydroclimatic conditions as well as annual lake level fluctuation for seasonal flood-control operations. This geomorphic mapping also provides an inventory of existing landforms from which to evaluate the spatial and temporal geomorphic change over time. Digital maps based on high-resolution digital surface models and orthophotographs acquired during low-pool conditions in 2023 extend over an area of about 30 square kilometers (km) upstream of the Fern Ridge Dam. The mapping framework has 3 main components consisting of several subtypes: 5 process domains, 18 landforms, and 7 cover categories. The overarching classification structure is tied to the process domains, which correspond to dissimilar regions of the reservoir that have distinct landforms and broadly similar suites of geomorphic processes. This document describes the geomorphic mapping framework for the reservoir at Fern Ridge Lake and provides mapping unit descriptions including delineation criteria, hypothesized formation processes inferred from remote-sensing and field observations and the literature, and relevance during drawdown operations.

Suggested Citation

Keith, M.K., and Bervid, H.D., 2025, Framework developed for geomorphic mapping of Fern Ridge Lake, Oregon, 2023: U.S. Geological Survey Data Report 1215, 33 p., https://doi.org/10.3133/dr1215.

ISSN: 2771-9448 (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Geomorphic Mapping Methods
  • Summary
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Framework developed for geomorphic mapping of Fern Ridge Lake, Oregon, 2023
Series title Data Report
Series number 1215
DOI 10.3133/dr1215
Publication Date September 04, 2025
Year Published 2025
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Oregon Water Science Center
Description Report: viii, 33 p.; Data Release
Country United States
State Oregon
Other Geospatial Fern Ridge Lake
Online Only (Y/N) Y
Additional publication details